Embodiments of the invention relate to aircraft propeller deicing systems, and more particularly, to brush block assemblies for use in propeller deicing systems.
Propeller deicing systems are used to prevent ice build-up on an aircraft's propeller blades. The most common type of deicing system uses resistive heating elements, such as in the form of flexible strips for example, which are disposed along a section of the blade's leading edge closest to the hub assembly. The application of electrical current to the heaters weakens the bond between accumulated ice and the airfoil surface allowing the ice to the “thrown off” by the centrifugal forces generated by rotation of the propeller.
An aircraft power source located on the non-rotating side of the propeller-engine interface provides electrical current to the brushes and through a rotating interface. The interface includes stationary, electrically conductive brushes which are in electrical contact with a conductive slip ring mounted to the rear of the rotating propeller's spinner assembly. The power required for deicing a propeller can be substantial i.e., around two KV per blade. Because of the power requirements, propellers having a large number of blades, such as four or more propeller blades for example, are commonly de-iced in pairs to minimize the peak power requirements of the aircraft and to reduce the likelihood of unbalance due to ice shedding.